Effect of Furnace Atmosphere on Chemical States of Copper in Ceramics
| Project/Area Number |
60470074
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学
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| Research Institution | Kyoto Institute of Technology |
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Principal Investigator |
WAKAMATSU Mitsuru Faculty of Engineering and Design, Kyoto Institute of Technology , Professor, 工芸学部, 教授 (00027781)
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| Co-Investigator(Kenkyū-buntansha) |
ISHIDA Shingo Faculty of Engineering, Chubu University , Associate Professor, 工学部, 助教授 (00102765)
TAKEUCHI Nobuyuki Faculty of Engineering and Design, Kyoto Institute of Technology , Research Asso, 工芸学部, 助手 (50154977)
SHIMIZU Satoshi Faculty of Engineering and Design, Kyoto Institute of Technology , Lecturer, 工芸学部, 講師 (20027783)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1985: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | Color of Glaze / Furnace Atmosphere / Copper Glaze / ESR of Copper Glaze / Copper Red Glass / Striking of Copper Red Glass / 還元焼成 |
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| Research Abstract |
Porcelain bodies applied with copper glaze were heated to 1300゜C under various atmospheres in the same firing schedule. Colors of the glaze samples obtained were classified by reflectance spectroscopy. The mode of the copper distribution and its oxidation state in the glaze were examined by EPMA, EDX and ESR. The copper glaze was grey and green for reducing and oxidizing atmospheres respectively. Red copper glaze was obtained by heating in reducing atmosphere followed by cooling in oxidizing one.
From ESR analyses, it was found that the red glaze consisted of <Cu^(2+)> as well as <Cu^+> , as was assumed from the equilibrium condition. The result denied the conventional theory that the red coloration is caused mainly by metallic copper colloid. The red chromophore in red copper glaze was assumed to be <Cu_2> O.The copper in glazes volatilized remarkably during the reducing firing.
ESR and ESCA analyses of a copper red glaze prepared by firing under a strongly reducing atmosphere followed by oxidation during a cooling period showed that <Cu^(1+)> and <Cu_2> o were major species in it. From the investigation of behavior and chemical states of copper and tin under various firing conditions, mechanisms of the formation of <Cu_2> O and its protection were assumed as follows: <Cu^(2+)> and <Sn^(4+)> are reduced to metals during reducing firing and then the metals aggregate in the glaze surface layer, forming alloy.
In the next oxidation process, metallic copper and tin are oxidized to <Cu_2> O or <Cu^(1+)> and SnO respectively. Due to the affinity of SnO on <Cu_2> O for glass, glass containing <Sn^(2+)> surrounds and consequently protects <Cu_2> O from excessive oxidation.
A colorless copper glass before striking contained copper mainly as <Cu^(1+)> . ESCA analysis showed that striking of the glass caused the selective formation of <Cu_2> O.
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Report
(1 results)
Research Products
(6 results)
